The present invention relates to a means by which printed images, especially those produced using an ink jet printer, may be transferred to a textile substrate. The system allows the images to be applied by the action of heat and pressure, by means for example of an iron.
Systems with which printer-produced images may be applied to textile substrates such as articles of clothing, especially T-shirts and sweatshirts, bags and the like in a simple procedure are increasingly being demanded by the consumer. The reason for this is that a high percentage of households now possess a computer with a printer connected to it, in many cases a colour printer. The images produced by the computer can therefore be transferred without problems to a substrate, generally paper, using the printer. As a result of the electronic media nowadays available, in conjunction with current communication techniques, it is possible to produce images from a virtually infinite variety of sources. Digital still cameras, video cameras, and the Internet are just some of those that may be mentioned. As a result, many consumers foster the desire to print the images available via the computer and to transfer them to a textile substrate such as an item of clothing. This should be realizable as simply as possible.
For this purpose, the prior art proposes a variety of solutions. U.S. Pat. No. 5,501,902 discloses a printable material consisting of a first support layer on which there is a second layer of a material which consists of a film-forming binder material and particles of a thermoplastic polymer with particle sizes of up to max. 50 μm. The particles consist of polyolefins, polyesters and ethylene-vinyl acetate copolymers. The printable material may be configured so that it is able to accept ink jet-printed images and to transfer them by the action of heat to a textile substrate. In this embodiment, an ink viscosity modifier is added; in order to achieve transferability to the substrate, the second layer includes a cationic polymer; in that case there is also, preferably, an additional melt transfer layer between the first support layer and the second layer.
DE 197 31 498 discloses an ink transfer sheet for applying ink jet-printed images to a textile substrate. The transfer sheet comprises a backing layer on which there is an interlayer of a meltable material which serves for fixing on the substrate. Above the interlayer there is an ink receiver layer on which there is applied in turn a layer of a quaternary ammonium salt, which serves to fix the ink.
Finally, WO 98/30749 discloses an ink transfer system comprising a substrate material, a melt transfer layer applied to the substrate material, and at least one ink-absorbing layer present on the said melt transfer layer. The system is characterized in that the ink-absorbing layer comprises a mixture of a highly porous filler and a binder, the molecules of the filler being capable of forming chemical bonds with the dye molecules of the ink. The fillers used are special highly porous polyamides which are intended to enter into a chemical bond with the dye.
The reasonably capable transfer systems disclosed in the aforementioned documents are all of a construction in which, on the first layer, which acts as the substrate, there is first a meltable layer which by the time of transfer melts by means of the applied heat and, following solidification, ensures adhesion to the textile substrate. Atop this layer there is then at least one further layer which serves to absorb the ink and has corresponding materials, generally an organic binder and also substances which are intended to ensure ink absorbability.
The placing of at least two different layers, however, is comparatively complex and generally undesirable, since it is necessary to assemble different materials for these layers which must then each be applied, meaning that the backing must also be coated a number of times accordingly. As a result, coating is time consuming, and the use of different materials necessitates a plurality of mixing operations.